Fix clippy lints

.github/workflows/build.yml

@@ -101,6 +101,18 @@ jobs:
       - name: cargo fmt --check
         run: cargo fmt --all -- --check
 
+  clippy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+          targets: i686-unknown-linux-gnu
+      - run: cargo clippy --all --target i686-unknown-linux-gnu -- --deny warnings
+
   # Compilation check
   check:
     name: check

CHANGELOG.md

@@ -7,7 +7,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
-- configure `stable_deref_trait` as a platform-dependent dependency
+### Changed
+
+- Changed `stable_deref_trait` to a platform-dependent dependency.
+
+### Fixed
+
+- Fixed clippy lints.
 
 ## [v0.8.0] - 2023-11-07
 

src/binary_heap.rs

@@ -233,7 +233,7 @@ where
     /// assert_eq!(heap.peek(), Some(&5));
     /// ```
     pub fn peek(&self) -> Option<&T> {
-        self.data.as_slice().get(0)
+        self.data.as_slice().first()
     }
 
     /// Returns a mutable reference to the greatest item in the binary heap, or
@@ -297,6 +297,7 @@ where
 
     /// Removes the *top* (greatest if max-heap, smallest if min-heap) item from the binary heap and
     /// returns it, without checking if the binary heap is empty.
+    #[allow(clippy::missing_safety_doc)] // TODO
     pub unsafe fn pop_unchecked(&mut self) -> T {
         let mut item = self.data.pop_unchecked();
 
@@ -330,6 +331,7 @@ where
     }
 
     /// Pushes an item onto the binary heap without first checking if it's full.
+    #[allow(clippy::missing_safety_doc)] // TODO
     pub unsafe fn push_unchecked(&mut self, item: T) {
         let old_len = self.len();
         self.data.push_unchecked(item);

src/deque.rs

@@ -283,7 +283,7 @@ impl<T, const N: usize> Deque<T, N> {
         let index = self.front;
         self.full = false;
         self.front = Self::increment(self.front);
-        (self.buffer.get_unchecked_mut(index).as_ptr() as *const T).read()
+        self.buffer.get_unchecked_mut(index).as_ptr().read()
     }
 
     /// Removes an item from the back of the deque and returns it, without checking that the deque
@@ -297,7 +297,7 @@ impl<T, const N: usize> Deque<T, N> {
 
         self.full = false;
         self.back = Self::decrement(self.back);
-        (self.buffer.get_unchecked_mut(self.back).as_ptr() as *const T).read()
+        self.buffer.get_unchecked_mut(self.back).as_ptr().read()
     }
 
     /// Appends an `item` to the front of the deque

src/histbuf.rs

@@ -117,6 +117,21 @@ impl<T, const N: usize> HistoryBuffer<T, N> {
         }
     }
 
+    /// Returns true if the buffer is empty.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use heapless::HistoryBuffer;
+    ///
+    /// let x: HistoryBuffer<u8, 16> = HistoryBuffer::new();
+    /// assert!(x.is_empty());
+    /// ```
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     /// Returns the capacity of the buffer, which is the length of the
     /// underlying backing array.
     #[inline]
@@ -219,7 +234,7 @@ impl<T, const N: usize> HistoryBuffer<T, N> {
     /// }
     ///
     /// ```
-    pub fn oldest_ordered<'a>(&'a self) -> OldestOrdered<'a, T, N> {
+    pub fn oldest_ordered(&self) -> OldestOrdered<'_, T, N> {
         if self.filled {
             OldestOrdered {
                 buf: self,

src/indexmap.rs

@@ -1,7 +1,7 @@
 use core::{
     borrow::Borrow,
     fmt,
-    hash::{BuildHasher, Hash, Hasher as _},
+    hash::{BuildHasher, Hash},
     iter::FromIterator,
     mem,
     num::NonZeroU32,
@@ -64,7 +64,7 @@ impl HashValue {
     }
 
     fn probe_distance(&self, mask: usize, current: usize) -> usize {
-        current.wrapping_sub(self.desired_pos(mask) as usize) & mask
+        current.wrapping_sub(self.desired_pos(mask)) & mask
     }
 }
 
@@ -364,7 +364,7 @@ where
     fn clone(&self) -> Self {
         Self {
             entries: self.entries.clone(),
-            indices: self.indices.clone(),
+            indices: self.indices,
         }
     }
 }
@@ -961,7 +961,7 @@ where
         K: Borrow<Q>,
         Q: ?Sized + Hash + Eq,
     {
-        if self.len() == 0 {
+        if self.is_empty() {
             return None;
         }
         let h = hash_with(key, &self.build_hasher);
@@ -1238,9 +1238,7 @@ where
     K: ?Sized + Hash,
     S: BuildHasher,
 {
-    let mut h = build_hasher.build_hasher();
+    HashValue(build_hasher.hash_one(key) as u16)
-    key.hash(&mut h);
-    HashValue(h.finish() as u16)
 }
 
 #[cfg(test)]

src/linear_map.rs

@@ -448,6 +448,7 @@ pub struct Iter<'a, K, V> {
 impl<'a, K, V> Iterator for Iter<'a, K, V> {
     type Item = (&'a K, &'a V);
 
+    #[allow(clippy::needless_borrowed_reference)]
     fn next(&mut self) -> Option<Self::Item> {
         self.iter.next().map(|&(ref k, ref v)| (k, v))
     }

src/mpmc.rs

@@ -145,7 +145,8 @@ impl<T, const N: usize> MpMcQueue<T, N> {
         crate::sealed::power_of_two::<N>();
 
         // Const assert on size.
-        Self::ASSERT[!(N < (IntSize::MAX as usize)) as usize];
+        #[allow(clippy::no_effect)]
+        Self::ASSERT[(N >= (IntSize::MAX as usize)) as usize];
 
         let mut cell_count = 0;
 
@@ -204,6 +205,7 @@ impl<T> Cell<T> {
     }
 }
 
+#[allow(clippy::comparison_chain)]
 unsafe fn dequeue<T>(
     buffer: *mut Cell<T>,
     dequeue_pos: &AtomicTargetSize,
@@ -243,6 +245,7 @@ unsafe fn dequeue<T>(
     Some(data)
 }
 
+#[allow(clippy::comparison_chain)]
 unsafe fn enqueue<T>(
     buffer: *mut Cell<T>,
     enqueue_pos: &AtomicTargetSize,

src/pool/arc.rs

@@ -221,7 +221,7 @@ where
     P: ArcPool,
 {
     fn as_ref(&self) -> &P::Data {
-        &**self
+        self
     }
 }
 

src/sealed.rs

@@ -1,29 +1,24 @@
-#[allow(dead_code)]
+#[allow(dead_code, path_statements, clippy::no_effect)]
-#[allow(path_statements)]
 pub(crate) const fn smaller_than<const N: usize, const MAX: usize>() {
     Assert::<N, MAX>::LESS;
 }
 
-#[allow(dead_code)]
+#[allow(dead_code, path_statements, clippy::no_effect)]
-#[allow(path_statements)]
 pub(crate) const fn greater_than_eq_0<const N: usize>() {
     Assert::<N, 0>::GREATER_EQ;
 }
 
-#[allow(dead_code)]
+#[allow(dead_code, path_statements, clippy::no_effect)]
-#[allow(path_statements)]
 pub(crate) const fn greater_than_0<const N: usize>() {
     Assert::<N, 0>::GREATER;
 }
 
-#[allow(dead_code)]
+#[allow(dead_code, path_statements, clippy::no_effect)]
-#[allow(path_statements)]
 pub(crate) const fn greater_than_1<const N: usize>() {
     Assert::<N, 1>::GREATER;
 }
 
-#[allow(dead_code)]
+#[allow(dead_code, path_statements, clippy::no_effect)]
-#[allow(path_statements)]
 pub(crate) const fn power_of_two<const N: usize>() {
     Assert::<N, 0>::GREATER;
     Assert::<N, 0>::POWER_OF_TWO;
@@ -42,6 +37,7 @@ impl<const L: usize, const R: usize> Assert<L, R> {
     pub const LESS_EQ: usize = R - L;
 
     /// Const assert hack
+    #[allow(clippy::erasing_op)]
     pub const NOT_EQ: isize = 0 / (R as isize - L as isize);
 
     /// Const assert hack

src/sorted_linked_list.rs

@@ -310,7 +310,8 @@ where
     /// ```
     pub fn push(&mut self, value: T) -> Result<(), T> {
         if !self.is_full() {
-            Ok(unsafe { self.push_unchecked(value) })
+            unsafe { self.push_unchecked(value) }
+            Ok(())
         } else {
             Err(value)
         }
@@ -462,6 +463,7 @@ where
     /// assert_eq!(ll.pop(), Ok(1));
     /// assert_eq!(ll.pop(), Err(()));
     /// ```
+    #[allow(clippy::result_unit_err)]
     pub fn pop(&mut self) -> Result<T, ()> {
         if !self.is_empty() {
             Ok(unsafe { self.pop_unchecked() })

src/spsc.rs

@@ -251,7 +251,7 @@ impl<T, const N: usize> Queue<T, N> {
 
     /// Adds an `item` to the end of the queue, without checking if it's full
     ///
-    /// # Unsafety
+    /// # Safety
     ///
     /// If the queue is full this operation will leak a value (T's destructor won't run on
     /// the value that got overwritten by `item`), *and* will allow the `dequeue` operation
@@ -295,7 +295,7 @@ impl<T, const N: usize> Queue<T, N> {
     /// Returns the item in the front of the queue, without checking if there is something in the
     /// queue
     ///
-    /// # Unsafety
+    /// # Safety
     ///
     /// If the queue is empty this operation will return uninitialized memory.
     pub unsafe fn dequeue_unchecked(&mut self) -> T {
@@ -507,7 +507,9 @@ impl<'a, T, const N: usize> Consumer<'a, T, N> {
     /// Returns the item in the front of the queue, without checking if there are elements in the
     /// queue
     ///
-    /// See [`Queue::dequeue_unchecked`] for safety
+    /// # Safety
+    ///
+    /// See [`Queue::dequeue_unchecked`]
     #[inline]
     pub unsafe fn dequeue_unchecked(&mut self) -> T {
         self.rb.inner_dequeue_unchecked()
@@ -526,6 +528,22 @@ impl<'a, T, const N: usize> Consumer<'a, T, N> {
         self.rb.len()
     }
 
+    /// Returns true if the queue is empty
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use heapless::spsc::Queue;
+    ///
+    /// let mut queue: Queue<u8, 235> = Queue::new();
+    /// let (mut producer, mut consumer) = queue.split();
+    /// assert!(consumer.is_empty());
+    /// ```
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     /// Returns the maximum number of elements the queue can hold
     #[inline]
     pub fn capacity(&self) -> usize {
@@ -536,6 +554,7 @@ impl<'a, T, const N: usize> Consumer<'a, T, N> {
     /// empty
     ///
     /// # Examples
+    ///
     /// ```
     /// use heapless::spsc::Queue;
     ///
@@ -562,7 +581,9 @@ impl<'a, T, const N: usize> Producer<'a, T, N> {
 
     /// Adds an `item` to the end of the queue, without checking if the queue is full
     ///
-    /// See [`Queue::enqueue_unchecked`] for safety
+    /// # Safety
+    ///
+    /// See [`Queue::enqueue_unchecked`]
     #[inline]
     pub unsafe fn enqueue_unchecked(&mut self, val: T) {
         self.rb.inner_enqueue_unchecked(val)
@@ -581,6 +602,22 @@ impl<'a, T, const N: usize> Producer<'a, T, N> {
         self.rb.len()
     }
 
+    /// Returns true if the queue is empty
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use heapless::spsc::Queue;
+    ///
+    /// let mut queue: Queue<u8, 235> = Queue::new();
+    /// let (mut producer, mut consumer) = queue.split();
+    /// assert!(producer.is_empty());
+    /// ```
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     /// Returns the maximum number of elements the queue can hold
     #[inline]
     pub fn capacity(&self) -> usize {
@@ -894,14 +931,12 @@ mod tests {
         let hash1 = {
             let mut hasher1 = hash32::FnvHasher::default();
             rb1.hash(&mut hasher1);
-            let hash1 = hasher1.finish();
+            hasher1.finish()
-            hash1
         };
         let hash2 = {
             let mut hasher2 = hash32::FnvHasher::default();
             rb2.hash(&mut hasher2);
-            let hash2 = hasher2.finish();
+            hasher2.finish()
-            hash2
         };
         assert_eq!(hash1, hash2);
     }

src/string.rs

@@ -209,6 +209,7 @@ impl<const N: usize> String<N> {
     /// # Ok::<(), ()>(())
     /// ```
     #[inline]
+    #[allow(clippy::result_unit_err)]
     pub fn push_str(&mut self, string: &str) -> Result<(), ()> {
         self.vec.extend_from_slice(string.as_bytes())
     }
@@ -251,6 +252,7 @@ impl<const N: usize> String<N> {
     /// # Ok::<(), ()>(())
     /// ```
     #[inline]
+    #[allow(clippy::result_unit_err)]
     pub fn push(&mut self, c: char) -> Result<(), ()> {
         match c.len_utf8() {
             1 => self.vec.push(c as u8).map_err(|_| {}),
@@ -315,7 +317,7 @@ impl<const N: usize> String<N> {
     /// Ok::<(), ()>(())
     /// ```
     pub fn pop(&mut self) -> Option<char> {
-        let ch = self.chars().rev().next()?;
+        let ch = self.chars().next_back()?;
 
         // pop bytes that correspond to `ch`
         for _ in 0..ch.len_utf8() {
@@ -518,21 +520,13 @@ impl<const N1: usize, const N2: usize> PartialEq<String<N2>> for String<N1> {
     fn eq(&self, rhs: &String<N2>) -> bool {
         str::eq(&**self, &**rhs)
     }
-
-    fn ne(&self, rhs: &String<N2>) -> bool {
-        str::ne(&**self, &**rhs)
-    }
 }
 
 // String<N> == str
 impl<const N: usize> PartialEq<str> for String<N> {
     #[inline]
     fn eq(&self, other: &str) -> bool {
-        str::eq(&self[..], &other[..])
+        str::eq(self, other)
-    }
-    #[inline]
-    fn ne(&self, other: &str) -> bool {
-        str::ne(&self[..], &other[..])
     }
 }
 
@@ -540,11 +534,7 @@ impl<const N: usize> PartialEq<str> for String<N> {
 impl<const N: usize> PartialEq<&str> for String<N> {
     #[inline]
     fn eq(&self, other: &&str) -> bool {
-        str::eq(&self[..], &other[..])
+        str::eq(self, &other[..])
-    }
-    #[inline]
-    fn ne(&self, other: &&str) -> bool {
-        str::ne(&self[..], &other[..])
     }
 }
 
@@ -552,11 +542,7 @@ impl<const N: usize> PartialEq<&str> for String<N> {
 impl<const N: usize> PartialEq<String<N>> for str {
     #[inline]
     fn eq(&self, other: &String<N>) -> bool {
-        str::eq(&self[..], &other[..])
+        str::eq(self, &other[..])
-    }
-    #[inline]
-    fn ne(&self, other: &String<N>) -> bool {
-        str::ne(&self[..], &other[..])
     }
 }
 
@@ -564,11 +550,7 @@ impl<const N: usize> PartialEq<String<N>> for str {
 impl<const N: usize> PartialEq<String<N>> for &str {
     #[inline]
     fn eq(&self, other: &String<N>) -> bool {
-        str::eq(&self[..], &other[..])
+        str::eq(self, &other[..])
-    }
-    #[inline]
-    fn ne(&self, other: &String<N>) -> bool {
-        str::ne(&self[..], &other[..])
     }
 }
 

src/vec.rs

@@ -76,6 +76,7 @@ impl<T, const N: usize> Vec<T, N> {
     /// v.extend_from_slice(&[1, 2, 3]).unwrap();
     /// ```
     #[inline]
+    #[allow(clippy::result_unit_err)]
     pub fn from_slice(other: &[T]) -> Result<Self, ()>
     where
         T: Clone,
@@ -210,6 +211,7 @@ impl<T, const N: usize> Vec<T, N> {
     /// vec.extend_from_slice(&[2, 3, 4]).unwrap();
     /// assert_eq!(*vec, [1, 2, 3, 4]);
     /// ```
+    #[allow(clippy::result_unit_err)]
     pub fn extend_from_slice(&mut self, other: &[T]) -> Result<(), ()>
     where
         T: Clone,
@@ -257,7 +259,7 @@ impl<T, const N: usize> Vec<T, N> {
         debug_assert!(!self.is_empty());
 
         self.len -= 1;
-        (self.buffer.get_unchecked_mut(self.len).as_ptr() as *const T).read()
+        self.buffer.get_unchecked_mut(self.len).as_ptr().read()
     }
 
     /// Appends an `item` to the back of the collection
@@ -305,6 +307,7 @@ impl<T, const N: usize> Vec<T, N> {
     /// new_len is less than len, the Vec is simply truncated.
     ///
     /// See also [`resize_default`](Self::resize_default).
+    #[allow(clippy::result_unit_err)]
     pub fn resize(&mut self, new_len: usize, value: T) -> Result<(), ()>
     where
         T: Clone,
@@ -331,6 +334,7 @@ impl<T, const N: usize> Vec<T, N> {
     /// If `new_len` is less than `len`, the `Vec` is simply truncated.
     ///
     /// See also [`resize`](Self::resize).
+    #[allow(clippy::result_unit_err)]
     pub fn resize_default(&mut self, new_len: usize) -> Result<(), ()>
     where
         T: Clone + Default,
@@ -934,9 +938,7 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> {
     type Item = T;
     fn next(&mut self) -> Option<Self::Item> {
         if self.next < self.vec.len() {
-            let item = unsafe {
+            let item = unsafe { self.vec.buffer.get_unchecked_mut(self.next).as_ptr().read() };
-                (self.vec.buffer.get_unchecked_mut(self.next).as_ptr() as *const T).read()
-            };
             self.next += 1;
             Some(item)
         } else {
@@ -1001,7 +1003,7 @@ where
     A: PartialEq<B>,
 {
     fn eq(&self, other: &[B]) -> bool {
-        <[A]>::eq(self, &other[..])
+        <[A]>::eq(self, other)
     }
 }
 
@@ -1011,7 +1013,7 @@ where
     A: PartialEq<B>,
 {
     fn eq(&self, other: &Vec<A, N>) -> bool {
-        <[A]>::eq(other, &self[..])
+        <[A]>::eq(other, self)
     }
 }
 

tests/tsan.rs

@@ -88,7 +88,7 @@ fn contention() {
 
                 for i in 0..(2 * N) {
                     sum = sum.wrapping_add(i as u32);
-                    while let Err(_) = p.enqueue(i as u8) {}
+                    while p.enqueue(i as u8).is_err() {}
                 }
 
                 println!("producer: {}", sum);
@@ -137,7 +137,7 @@ fn mpmc_contention() {
             for i in 0..(16 * N) {
                 sum = sum.wrapping_add(i);
                 println!("enqueue {}", i);
-                while let Err(_) = Q.enqueue(i) {}
+                while Q.enqueue(i).is_err() {}
             }
 
             s1.send(sum).unwrap();